Fuse holder

Abstract

A fuse holder provides a safe device for connecting fuses to a three-phase busbar device. Each phase includes a corresponding load conductor and line conductor mounted within a housing. A mechanical lock is provided for each phase that locks a knife of the fuse to one of the conductors for the phase. In a further aspect, the fuse knives are frictionally locked within the housing. In both the mechanical lock and frictional lock, a release mechanism is provided that can be activated by a screwdriver to release the fuse knives from the fuse holder. In another aspect, certain conductors are provided with heat dissipation wings that contact the housing to dissipate heat generated by current flowing through the conductor.

What is claimed is: 
     
       1. A fuse holder for connecting a fuse, having a pair of knives, to a busbar device, the fuse holder comprising:
 a housing defining;
 a pair of fuse contact openings in a front face of the housing configured to receive the knives of the fuse in a respective one of the contact openings when the fuse is inserted into the fuse holder; and 
 a busbar contact opening in a back face of the housing; 
 
 a wire terminal mounted within said housing and accessible for electrical connection with a wire of an external device; 
 a line conductor mounted within said housing and including;
 a fuse contact portion aligned with one of the pair of fuse contact openings to contact a knife of the fuse received through said fuse contact opening, and 
 a busbar contact portion extending through said busbar contact opening and configured for electrical connection to the busbar device when the fuse holder is mounted on the busbar device; 
 
 a load conductor mounted within said housing and including;
 a fuse contact portion aligned with the other of the pair of fuse contact openings to contact a knife of the fuse received through said fuse contact opening, and 
 a terminal contact portion in contact with said wire terminal; 
 
 an engagement mechanism for releasably engaging the fuse holder to the busbar device; and 
 a locking mechanism for releasably locking at least one knife of the fuse to the fuse holder. 
 
     
     
       2. The fuse holder of  claim 1 , in which at least one knife of the fuse includes an opening therethrough,
 wherein one conductor of said line conductor and said load conductor includes a hole therethrough that is aligned with the hole in the at least one knife of the fuse when the knives are received in the contact openings of the fuse holder; and 
 the locking mechanism includes a locking member disposed within said housing and slidable relative to said one conductor, said locking member configured to simultaneously engage the hole in said one conductor and in the hole in the knife when the knives are received in the contact openings of the fuse holder, to prevent removal of the knife from the fuse holder. 
 
     
     
       3. The fuse holder of  claim 2 , wherein the locking mechanism includes an elongated carriage slidably disposed within said housing, said carriage including;
 a needle forming said locking member and extending from one end of said carriage that is aligned with said hole in said one conductor and sized to extend through said hole in said one conductor and said hole in said knife in a locking position; 
 a spring disposed between said needle and said plate arrangement configured to bias said needle to said locking position. 
 
     
     
       4. The fuse holder of  claim 3 , wherein said needle includes a beveled tip that is arranged to be contacted by the knife as the knife is inserted into the fuse holder to push the needle against the spring. 
     
     
       5. The fuse holder of  claim 3 , wherein said carriage further comprises a cam element disposed at an opposite end of said carriage, said cam element defining a curved surface configured to move said carriage away from said locking position upon engagement with a tool against said curved surface. 
     
     
       6. The fuse holder of  claim 1 , further comprising a plate arrangement mounted within said housing configured to support, in fixed relation to said housing, said load conductor and said line conductor so that said fuse contact portions of the load conductor and line conductor are each aligned with a corresponding one of said pair of fuse contact openings, said plate arrangement further configured to support said line conductor so that said busbar contact portion extends through said busbar contact opening and to support said load conductor so that said terminal contact portion is in electrical contact with said wire terminal. 
     
     
       7. A fuse holder for connecting a fuse, having a pair of knives, to a busbar device, in which the fuse holder is configured for connecting three fuses to a three-phase electrical line, the fuse holder comprising:
 a housing defining;
 for each of the three fuses, a pair of fuse contact openings in a front face of the housing configured to receive the knives of the fuse in a respective one of the contact openings when the corresponding fuse is inserted into the fuse holder; and 
 a busbar contact opening in a back face of the housing; 
 
 a wire terminal mounted within said housing and accessible for electrical connection with a wire of an external device; 
 for each of the three fuses, a line conductor mounted within said housing and including;
 a fuse contact portion aligned with one of the pair of fuse contact openings to contact a knife of the corresponding fuse received through said fuse contact opening, and 
 a busbar contact portion extending through said busbar contact opening and configured for electrical connection to the busbar device when the fuse holder is mounted on the busbar device; 
 
 for each of the three fuses, a load conductor mounted within said housing and including;
 a fuse contact portion aligned with the other of the pair of fuse contact openings to contact a knife of the corresponding fuse received through said fuse contact opening, and 
 a terminal contact portion in contact with said wire terminal; and 
 
 an engagement mechanism for releasably engaging the fuse holder to the busbar device, 
 wherein the line conductors for each of the three phases are configured so that the busbar contact portions of the line conductors are vertically separated along a length of said housing for electrical engagement to the busbar device. 
 
     
     
       8. The fuse holder of  claim 7 ,
 wherein said load conductor and said line conductor for two of the three phases are configured so that the corresponding fuse contact portions are laterally adjacent each other; and 
 said load conductor and said line conductor for the third of the three phases is configured so that the corresponding fuse contact portions are vertically adjacent the corresponding fuse contact portions for the other two phases along the length of the housing. 
 
     
     
       9. The fuse holder of  claim 7 , wherein said housing defines, for each of the three fuses, a fuse bay including a recess in a front face of said housing configured to receive the corresponding fuse therein, said pair of fuse contact openings for each of the three fuses arranged in a corresponding recess. 
     
     
       10. The fuse holder of  claim 9 ,
 wherein said fuse bay for each of the three phases includes indicia indicative of the corresponding one of the three phases. 
 
     
     
       11. A fuse holder of  claim 1 , further comprising:
 a plate arrangement mounted within said housing configured to support, in fixed relation to said housing, said load conductor and said line conductor so that said fuse contact portions of the load and line conductors are each aligned with a corresponding one of the pair of fuse contact openings, said plate arrangement further configured to support said line conductor so that said busbar contact portion extends through said busbar contact opening and to support said load conductor so that said terminal contact portion is in electrical contact with said wire terminal; 
 wherein said locking mechanism includes; 
 a carriage slidably disposed within said housing and including a spring plate and pair of clamping plates, one each of the clamping plates facing the fuse contact portion of a corresponding one of the line conductor and the load conductor; and 
 a biasing spring disposed between said plate arrangement and said spring plate, said biasing spring configured to exert a spring force on said spring plate of said carriage to bias said clamping plates toward the fuse contact portions of the corresponding line and load conductor; 
 wherein the fuse contact openings are arranged so that, when the fuse is inserted into the fuse holder, each of the pair of knives of the fuse is inserted between and in frictional engagement with the fuse contact portion, of a corresponding one of the line conductor and the load conductor, and a corresponding one of said clamping plates, to thereby move the carriage against the spring force exerted on the carriage. 
 
     
     
       12. The fuse holder of  claim 11 , further comprising:
 a tool opening defined in said housing; and 
 a release post on said carriage, said release post accessible by an elongated tool extending through said tool opening, said release post configured to move said carriage against the spring force exerted on the carriage to move said pair of clamping plates away from the fuse contact portions. 
 
     
     
       13. The fuse holder of  claim 12  wherein said release post and said tool opening are physically remote from the line and load conductors so that a tool extending through said tool opening to access said release post cannot contact the line and load conductors. 
     
     
       14. A fuse holder for connecting a fuse, having a pair of knives, to a busbar device, comprising:
 a housing defining;
 a pair of fuse contact openings in a front face of the housing configured to receive the knives of the fuse in a respective one of the contact openings when the fuse is inserted into the fuse holder; 
 a busbar contact opening in a back face of the housing; 
 an ejector opening defined in said housing; 
 an ejector slidably mounted in the ejector opening to contact the fuse when the fuse is inserted into the fuse holder; and 
 an ejector spring mounted within the housing to push the ejector through the ejector opening and against the fuse, said spring configured to push the ejector outward relative to the ejector opening against the fuse to dislodge the fuse from the fuse holder; 
 
 a wire terminal mounted within said housing and accessible for electrical connection with a wire of an external device; 
 a line conductor mounted within said housing and including;
 a fuse contact portion aligned with one of the pair of fuse contact openings to contact a knife of the fuse received through said fuse contact opening, and 
 a busbar contact portion extending through said busbar contact opening and configured for electrical connection to the busbar device when the fuse holder is mounted on the busbar device; 
 
 a load conductor mounted within said housing and including;
 a fuse contact portion aligned with the other of the pair of fuse contact openings to contact a knife of the fuse received through said fuse contact opening, and 
 a terminal contact portion in contact with said wire terminal; 
 
 an engagement mechanism for releasably engaging the fuse holder to the busbar device. 
 
     
     
       15. The fuse holder of  claim 14 , wherein said ejector opening is arranged between said pair of fuse contact openings defined in said housing. 
     
     
       16. The fuse holder of  claim 11 , wherein biasing spring is configured to generate a clamping force of 50-150 N to clamp each of the pair of knives between the corresponding fuse contact portion and the corresponding clamping plate.